President Trump and other world leaders offered their condolences to the victims of the New York terrorist attack on Tuesday, although Trump emphasized the apparent terrorist motivation of the alleged perpetrator.

Amid reports that that the hit-and-run driver, identified as Sayfullo Saipov, shouted ôAllahu Akbar,ö Trump tweeted that ôwe must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere. Enough!ö

Trump also tweeted that he ordered the Department of Homeland Security ôto step up our already Extreme Vetting Program.ö Earlier this month, Trump resumed refugee admissions into the United States, signing an executive order that lifted his previous seven-month moratorium and replacing it with what he has called "extreme vetting."

"I have just ordered Homeland Security to step up our already Extreme Vetting Program. Being politically correct is fine, but not for this!"

Earlier, Trump had tweeted that it ôlooks like another attack by a very sick and deranged person. Law enforcement is following this closely. NOT IN THE U.S.A.!ö

In another message, Trump tweeted that ômy thoughts, condolences and prayers to the victims and families of the New York City terrorist attack. God and your country are with you!ö

Saipov, driving a a rented pickup, plowed through a busy bicycle path near the World Trade Center memorial in Lower Manhattan on Tuesday and fatally struck eight people, then emerged screaming and brandishing "imitation firearms" before he was shot by police.

The stunning Halloween attack, just hours before the city's parade and festivities were to kick off, was confirmed as a terror incident by authorities at a late-afternoon news briefing.

World leaders also pledged to renew efforts to defeat terrorism in the wake of the attack.

ôAppalled by this cowardly attack, my thoughts are with all affected,ö tweeted British Prime Minister Theresa May. ôTogether we will defeat the evil of terrorism. UK stands with #NYC.ö

Former President Bill Clinton tweeted that ôNew Yorkers see this attack for what it isŚan attempt to sow fear. We stand against terror as we grieve for the victims and thank the @NYPD.ö